[lttng-dev] Using lttng-ust 2.13.6 from Yocto Kirkstone and getting weird segfault saying strlen_asimd.S can't be found.

[Brian Hutchinson]

Hi Kienan,

On Thu, Jul 11, 2024 at 8:38 AM Kienan Stewart <kstewart at efficios.com>
wrote:

> Hi Brian,
>
> On 7/11/24 8:33 AM, Brian Hutchinson via lttng-dev wrote:
>  > ...
>  >
>  > I'm not sure about this, still trying to comprehend everything, but I
>  > think my issue could be related to all this gcc TLS, heap, trampoline
>  > talk here:
>  >
>  > https://www.mail-archive.com/lttng-dev@lists.lttng.org/msg13584.html
>  > <https://www.mail-archive.com/lttng-dev@lists.lttng.org/msg13584.html>
>  >
>  > Regards,
>  >
>  > Brian
>  >
>
> You could try using lttng-ust 2.13.8, which includes a fix for the
> discussion you referenced.
>
>
> https://github.com/lttng/lttng-ust/commit/5db715e800d9b721f48495a987cd26c25965e836
>
> Please let us know if it doesn't solve it.
>
> thanks,
> kienan
>

I updated to lttng-ust 2.13.8 as you suggested.  At first, I pulled in the
recipe from master branch of Yocto, but had the same problem as before
after rebuilding.

Next, I downloaded the 2.13.8 lttng-ust tarball from the lttng site and
setup a native build environment on my target and built lttng-ust 2.13.8
and my app as a second independent build method for sanity check.  I can
report that I get the exact same result as before this way too.

In both cases, I verified that I had the commit you referenced above.

I did a backtrace of the three threads captured in the coredump and show
them below in hopes it will shed light on what I need to try next.

(gdb) thread apply all backtrace

Thread 3 (Thread 0xffffbe7de7e0 (LWP 559)):
#0  syscall () at ../sysdeps/unix/sysv/linux/aarch64/syscall.S:38
#1  0x0000ffffbeef1bb8 in lttng_ust_futex (val3=0, uaddr2=0x0, timeout=0x0,
val=0, op=0, uaddr=0xffffbefd8000) at ../../../src/lib/lttng-ust/futex.h:56
#2  lttng_ust_futex_async (op=0, val=0, timeout=0x0, uaddr2=0x0, val3=0,
uaddr=0xffffbefd8000) at ../../../src/lib/lttng-ust/futex.h:88
#3  wait_for_sessiond (sock_info=0xffffbef6b638 <global_apps>) at
lttng-ust-comm.c:1761
#4  ust_listener_thread (arg=0xffffbef6b638 <global_apps>) at
lttng-ust-comm.c:1832
#5  0x0000ffffbe9206a8 in start_thread (arg=0xffffc1bd8687) at
pthread_create.c:442
#6  0x0000ffffbe98801c in thread_start () at
../sysdeps/unix/sysv/linux/aarch64/clone.S:79

Thread 2 (Thread 0xffffbdfce7e0 (LWP 560)):
#0  syscall () at ../sysdeps/unix/sysv/linux/aarch64/syscall.S:38
#1  0x0000ffffbeef1bb8 in lttng_ust_futex (val3=0, uaddr2=0x0, timeout=0x0,
val=0, op=0, uaddr=0xffffbefd7000) at ../../../src/lib/lttng-ust/futex.h:56
#2  lttng_ust_futex_async (op=0, val=0, timeout=0x0, uaddr2=0x0, val3=0,
uaddr=0xffffbefd7000) at ../../../src/lib/lttng-ust/futex.h:88
#3  wait_for_sessiond (sock_info=0xffffbef695e0 <local_apps>) at
lttng-ust-comm.c:1761
#4  ust_listener_thread (arg=0xffffbef695e0 <local_apps>) at
lttng-ust-comm.c:1832
#5  0x0000ffffbe9206a8 in start_thread (arg=0xffffc1bd8687) at
pthread_create.c:442
#6  0x0000ffffbe98801c in thread_start () at
../sysdeps/unix/sysv/linux/aarch64/clone.S:79

Thread 1 (Thread 0xffffbefcf460 (LWP 545)):
#0  __strlen_asimd () at ../sysdeps/aarch64/multiarch/strlen_asimd.S:96
#1  0x0000ffffbe834bd0 in lttng_ust_tp_validate_event_name
(tp=0xaaaab8f14de0
<lttng_ust_tracepoint_hello_world___my_first_tracepoint>, tp=0xaaaab8f14de0
<lttng_ust_tracepoint_hello_world___my_first_tracepoint>) at
tracepoint.c:143
#2  add_callsite (tp=0xaaaab8f14de0
<lttng_ust_tracepoint_hello_world___my_first_tracepoint>,
lib=0xaaaae74fad30) at tracepoint.c:412
#3  lib_register_callsites (lib=0xaaaae74fad30) at tracepoint.c:552
#4  lttng_ust_tracepoint_module_register (tracepoints_start=<optimized
out>, tracepoints_count=<optimized out>) at tracepoint.c:956
#5  0x0000aaaab8758204 in lttng_ust.tracepoints.ptrs_init ()
#6  0x0000ffffbe8cb30c in call_init (env=<optimized out>,
argv=0xffffc1bd8c88, argc=1) at ../csu/libc-start.c:145
#7  __libc_start_main_impl (main=0xaaaab867aabc <main>, argc=1,
argv=0xffffc1bd8c88, init=<optimized out>, fini=<optimized out>,
rtld_fini=<optimized out>, stack_end=<optimized out>) at
../csu/libc-start.c:376
#8  0x0000aaaab867a7f0 in _start () at ../sysdeps/aarch64/start.S:81

Regards,

Brian
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